In general, a vehicle includes a side seal, a front pillar (A-pillar), a B-pillar, and a C-pillar at a later side of a vehicle at which a door is mounted.
Referring to FIG. 1, a side seal 1 has a floor panel fixed thereto, and a front pillar 2 is fixed to a front end of the side seal 1. A B-pillar 3 is fixed to a central portion of the side seal 1. A C-pillar 4 is fixed to a rear wheel house connected to a rear end of the side seal 1.
As illustrated in FIGS. 2 and 3, the front pillar 2 includes: a front pillar outer upper reinforcing member 5; a roof side outer reinforcing member 6 which is coupled to an upper end of the front pillar outer upper reinforcing member 5; a front pillar inner upper panel 7 inside the roof side outer reinforcing member 6; a roof side inner rail 8 which is coupled to an upper end of the front pillar inner upper panel 7; and a front pillar outer reinforcing member 9. The A-pillar 2 further includes a side outer panel for exterior use.
Rigidity of the front pillar, among other pillars, is very important to protect a driver when a front collision occurs.
When a cross section increases thus to increase the rigidity of the front pillar, an obstruction angle for a driver increases. Further, it is difficult to assemble a vehicle body when assembling an outer side. When a tubular reinforcing member 11 is added, as illustrated in FIG. 4, spot welding cannot be applied to fix the reinforcing member to the inner panel, and further, since CO2 welding is used, productivity deteriorates. In addition, it is difficult to improve a cross-sectional shape because a sealing shape needs to be maintained.
As a related art associated with a front pillar for a vehicle, there is a pipe reinforced member formed by hydroforming, which is fixed and welded to a roof inner panel. However, because spot welding cannot be applied to the pipe reinforced member, it is impossible to implement welding automation, and as a result, productivity deteriorates.
In another related art, a roof rail that forms a flange by hydroforming to form a tubular body and a longitudinally extending flange as a support rail which has a front pillar and a roof trail portion. However, welding is carried out after holes are formed in order to easily weld the flange, and as a result, productivity deteriorates, and a burst may occur at an end of the flange, which results in a number of defective products.
In addition, there has been introduced a structure in which a flange is formed at a front portion of a side rail inner panel and inserted into a pillar, and a roof reinforcing member, which has a door sealing flange, manufactured by pressure-resistant hydroforming.
The related art discloses a front pillar reinforced by hydroforming, however productivity is low and a burst phenomenon occurs at an end of a flange of the front pillar when forming the flange, thus reducing quality and rigidity.
The above information disclosed in this Background section is only for enhancement of understanding the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.